Dielectric properties and thermal behavior of electrolytic manganese anode mud in microwave field

Abstract

Exploring the dielectric properties of a material can provide guidance for applications of microwave technology to the material. In this work, dielectric properties and thermal behavior of manganese anode mud and pure MnO2, CaSO4 and PbSO4 components were systematically investigated. Results indicated that manganese anode mud showed excellent responsiveness to microwaves, with εr′ value of 17.971 (F/M) at room temperature and a maximum value of 20.816 (F/M) at 150 °C, rendering it took only 5.5 min for manganese anode mud to be heated from room temperature to 1000 °C. The dielectric properties of manganese anode mud were related to its thermal behavior, mainly affected by MnO2 component. Moreover, the heating process of manganese anode mud was divided into four stages identified by temperatures: less than 200 °C, 200 °C–700 °C, 700 °C–900 °C, greater than 900 °C, corresponding to the five stages of thermal behavior: the removal of absorption water and combined water, the decomposition reaction of Pb2Mn8O16, and the deoxidation reactions of PbO2, MnO2 and Mn3O4. The work highlights the feasibility of processing manganese anode mud by microwave heating.